<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>打印偶数</title>
</head>
<body>  
<script>
    const arr = [1,2,3,4,5,6,7,8,9];
    for (let i = 0; i < arr.length; i++) {
        const n = arr[i];
        if (n % 2 === 0) {
            console.log(n);
        }
    }

</script>
</body>
</html>